The present invention relates to Internet Protocol (IP) phone systems, IP phone terminal registration methodology, and devices adaptable for use therein, including but not limited to telephone terminals and main apparatus of an IP phone system.
Recent advances in IP networks such as the Internet and intranets result in development of a variety of new communication schemes via networks. In particular, the advent of IP telephones using voice over IP (VoIP) technologies leads to drastic changes in currently established telephone systems. A typical example of such IP phone systems is an extension telephone system for use in working environments of business entities.
Generally, the extension IP phone system is arranged to include an IP phone system main apparatus which manages telephone terminals involved or “subscribed” therein and performs call-up control for voice communications between these phone terminals. Various types of phone terminals are available, major examples of which are a wired IP phone that is directly linkable to IP network, a telephony software application on a personal computer (PC) with a speaker(s) and a microphone connected thereto, and a radiophone handset connectable via a wireless local area network (LAN) access point.
Upon establishment of such extension IP phone system, it is a must to allocate a unique IP address and extension telephone number to every telephony of the phone terminals involved. Simultaneously, it is also needed to register the setup information of these terminals to the main system controller. With all of these setup contents consolidated together while providing consistent compliance therebetween, the extension IP phone system is expected to offer proper operabilities and functionabilities required.
For the allocation of extension phone numbers, it is required to design, prior to system installation, a detailed numbering plan by taking into consideration multiple base points and the exact number of working staffs. Making this numbering plan is inherently a troublesome and time-consuming work. An exemplary approach to solving this problem is to use a method for automatically allocating extension numbers in deference to setup locations of phone terminals as disclosed, for example, in JP-A-2002-315029.
Regarding the telephone terminal IP address setup also, this must be carried out on a per-terminal basis in the event of system installation. A human work required therefor is also troublesome and consumes time. One thinkable method for reducing complexities in IP address allocation is to employ a specific scheme, known as the dynamic host configuration protocol (DHCP). DHCP is the protocol for assigning network information, such as IP addresses, to IP equipment linked to the IP network. Installing a DHCP device on IP network avoids the need for manual IP address setup operations as far as the telephones concerned are DHCP-supporting phone terminals. This makes it possible reduce a total amount of manual operations needed for setup of such IP telephone terminals.
The DHCP device has an ability to allocate a unique IP address to the individual DHCP-supporting IP equipment that is once linked to the IP network within a predetermined area or zone. Additionally for the DHCP, expanded functions are defined by request-for-comment (RFC) 2131 and RFC 2132 standards. Use of the expanded functions makes it possible to set up in option part various kinds of data indicated by tag numbers and to notify more detailed option data. An example is that an authorized period of service (lease time) is settable to an IP address as allocated by the DHCP device. Another example is that an ability is obtained to send IP addresses of a domain name server (DNS) and default gateway accessible from the terminal side while permitting achievement of automated setup thereof.
Unfortunately, the above-stated prior art approach suffers from the lack of any ability to acquire the IP address of the main apparatus in the event that an IP telephone terminal is newly registered to the IP phone system, although it is possible by DHCP to perform IP address setup and extension number allocation in an automated way. Consequently, it is still required for system maintenance service persons to perform manual telephone terminal setup operations for the individual IP phones. Upon installation of the IP phone system, a need is felt to register a great number of IP phone terminals around the same time. Usually a service person or persons perform manual operations for setup of IP phone terminals on a one-at-a-time basis; however, this approach is less in working efficiency. It has also been required to provide a setup method that is free from operation mistakes.